Thread cutter for shoe sewing machines



NOV. 25, 1952 s, CLARK 2,619,060

THREAD CUTTER FOR SHOE SEWING MACHINES Original Filed Nov. 16, 1948 fatented Nov. 25, 1952 UNITED stares ears-NT oFFice THREAD. CUTTER FOR SHOE! SEWINGv MACHINES I,

Alfred s. Clark; Beverly, Mass., assignor to United Shoe Machinery Corporation; FlemingtomNi J., altoorporationsoftNewsJersey Original application November. 16; 1948;. Serial" No. .60,'209; Divided and'this' applicatiomNo vember 23, 1949 Serial No: 129,033"- of thi-sstypes-is disclosed invUnited States-Letters RatenttNo; 710,612, granted October :7, v1902 uponapplicationof- E. P; Richardson, No. 1,114,287, granted October-20, 1914 upon application of EJJ.

Ray-and No. 1;'738:,7'78; granted December 10, 1929f upon applicationiof. B.- T; Iievequez. The-illusetrated machineis the same asthat more fully described in :an application for United StatesLetters- Patent :Ser; No; 60,209; filed November-16,1948, of which. the :present "application: is a :division;

An object of the invention 'is'to: provideanoveli and improved form ofthreadcutterfor a machine of the typezreterred; to',.@which l is.:oft simple. andl compact construction; and. .willioperate with re-iliability: and: with: greater efiective. cooperation witmtheiother: actuatingtzdevices of fthe machine than'witli ma'chineszof prior construction;v

One. difficulty in :providing: a machine having, aprotary-shoe supporting horn, with a thread 'cut- 1 ter 1' arises .from the: crowded relationship of the. stitchzformingr and work-.feedingl devices ofthe: machine at the upper side-of the work: opposite: the horn; Because of the crowded relationship of 3 these devices-tin prior machinesand :particularly because a-presser foot-is mounted above the work: directly inth'e seam line behind the needle; according to. .theusual practice, it is necessaryto provide a. retractable thread cutter which ismovable out-of the range of action in thesedevices to a a position where it will not interferewith-theirv operation or with the presentation oftheshoeby: the operator to. the operating point in the machine When Larranged for-movement out of the range of the operating devices, it is necessary to locate the thread cutter accurately when moved into operative position so that reliable severance of the thread will be accomplished.

I'n accordance with the object of the' invention a: retractable thread-cutter is provided; connected in spaced relation with a guide member actually engaging .theneedle to position the thread cutter: accurately relatively to the" needle loop I while:

severing the thread and to. disengage-the=need1'e:= for normal operation of the machinewhenmoved: out: of .1 the; range of; the stitcn' forming devices;. such" arrangementzissrenderedztpossibleiaby the mseiz'. of acpresserdevice disposedzout:oizlineawithathe seam. at 'the'rear.of:the needletwhereciti doesm' lHtBIfEIGiWi-th the; movements: of theqguideimfimv ber. Preferably, the guide member; issiforked toe engage. the. needle: while the;- thread: is? bein severed rand intone; form1of 'this:featurerthe guidezr member. is. mounted with-ma slot in ablcck-whichzialso: carries thecknife forrthe-thread cutter.- The: useaof a slotted :mountirieabloclcisoi advanta e? alsoiin. supporting.a..-guard.ior:the cuttinggedge of? the: knife; acting. to: protect the-work. operated: upon fromcontact with the knifewhilethe-thread; is being severed;

These. andg other features of the invention' conesist in the constructions; combinationsand -;,a rangements of parts here nafter describfid nds claimed,..theaadvantages-ofiwhich willireadily bea apparent from the .iollowing;descriptiorritaken connection with the accompany g-. drawings in which? Fig; 1-is:-a- :view in frontielevation of? a sewing; head and a portion of a rotarywork supporting;- horn :in" a machine embodying; a:- th-readcutter-1; having. thefeatures of the; present invention;

Fig. 2.21s aperspectivedetail view of theistraig htz hook needle in the machine: of Fi -'5 l;- he ppc-ri end of the work supporting;hormand the thread-4 cutterrgin inoperative position, illustrating the-rer lationship ofth'e parts;

Fig. 3; isa. similar view show-ing-theg-.thr.ead cutter-in operativeposition; and.

Fig. 4.15 a-perspective detail view ofaaimodifi-ed form of thread cutterin operative position.

The -machine illustrated in the drawings .-is-o f: the-' same constructionz and mode: of operation, exceptas hereinafter pointed out as .thated-is closedgin theqRichardsorr andRa-y patents abovea referred to. Referringyto Fig- .1 of the. drawings; the straight hookneedle is indicated at. latherotary shoe supporting horn= a-t' 4 and the feed; point at Otherstitch storming devices includ ing a castt-ofirl also are-provided actin'g dnring g sewing; tozdraw loo-pszof thread-.upwardly -througm the work .and'ito :set each'xstitch :by, tightenin the: loops against the work. Instead of; locating ther work 'clampingmember; alongthedine:ofttheseam in advance of the feed point according to common practice, a shoe sole 8, presented to the illustrated machine is, engaged along its upper surface by a clamping member in the form of a roll l close behind the needle at the rear side of the seam line opposite a circular shoe supporting portion [2 of the horn. The presser roll is rotatable on a shoulder screw l4 threaded into a bracket [6 secured to the lower end of a presser foot bar H3, in turn slidably mounted in the frame of the machine for clamping movement toward and from the work. The bracket 16 is formed with a laterally projecting slotted arm through which a clamping stud 20 is inserted to secure the bracket to the presser bar, all the presser roll supporting parts being disposed behind the needle and the seam line.

As has been stated, the arrangement of the presser roll (0 behind the seam line opposite the needle path and the elimination of the customary presser foot enables the use of the improved form of thread cutter. The thread cutter of the present invention is retractable from operating position, is manually actuated along the seam line and is guided accurately with relation to one side of aloop 22 of thread retained on the needle above the work after formation of the last stitch in a seam to permit reliable severing of the thread. By this arrangement the thread is severed close to each last formed stitch 24 while leaving sufficient thread between the needle and the horn to insure proper formation of the first stitch in the new seam.

The thread cutter comprises a knife 26 mounted to swing toward and from the needle path and to enter between the sides of the final loop of thread 22 on the needle at the end of a seam. The thread cutter knife is a flat blade, pointed at its cutting end with its forwardly facing edge at the point sharpened while the rearward edge remains unsharpened to avoid severing both sides of the needle loop. The knife is secured in a slot of a block 28 fastened to the lower end of a reversely bent actuating lever 33 guided to move along the seam line. The lever extends upwardly from the block 28 to a right angle bend, thence horizontally to a fulcrum stud 32 and then upwardly to a handle portion. The stud 32 projects from a plate 33 clamped to the presser foot supporting bar I8 and acts to guide the lever 30. The handle portion of the lever 30 also carries a stop clip 34 adjustably secured by a screw 36 passing through a slot in the clip, so arranged that the clip will engage the presser foot bar to limit the thread cutting movement of the knife 26 and prevent it from engagement with the other operating parts of the machine. The lever 30 is normally held in an inoperative position with the knife retracted out of the needle path by a tension spring 38 connected between a pin on the lever 30 and a pin of the machine frame.

To guide the movements of the knife 26 and to insure accurate entry between the sides of the loop 22 of thread carried by the needle, a second slot in the block 28 above the knife 26 supports a forked guide member 40 in parallel relation to the blade of the knife. The fork in the guide member provides an opening of sufiicient width to fit the diameter of the needle so that when it engages the needle the point of the knife is positioned without fail between the sides of the needle loop. The width of the guide member is such that it moves readily past the presser roll and its bracket 16.

- To prevent damage to a shoe bottom by engagement with the knife 26 the cutting edge of the knife is surrounded by the arms of a guard plate 42 mounted in the lower slot of the block 28. The guard plate 42 has one arm curved beneath and upwardly over the cutting edge of the knife from a location between the knife and the point on the shoe bottom operated on by the needle and another arm bent into a horizontal position to extend behind the needle loop and beyond the point of the knife to prevent accidental contact by the hands of the operator or by the work with the knife point.

In another form of the knife a guard plate is found unnecessary inasmuch as the forward edge of the knife is left unsharpened, the rearward edge only being employed to sever the thread. Such knife is indicated at 44 in Fig, 4 and is mounted in the same manner as in the previous arrangement within the lower slot of the block 28. The same guide member 40 also is employed with the unguarded knife 44. In this instance, however, the knife isso shaped that during its cutting stroke the rearward edge of the knife does not move rearwardly beyond the central axis of the needle, the knife cutting the forward side of the loop without enterin between the two sides. Also the use of a sharpened point on the knife is eliminated so that no guard is required in this instance for the point.

The nature and scope of the invention having been indicated and a particular embodiment having been described, what is claimed is:

l. A shoe sewing machine having a straight hook needle and other stitch forming devices acting during sewing to draw loops of thread through the work and to tighten the loops against the work, and a thread cutter comprising a knife arranged to sever the thread in a loop withdrawn from the work by the needle, in combination with a guide member operatively connected to and in spaced relation above the knife for positioning the thread cutter relatively to the needle loop by engagement with the needle while the knife is being actuated to sever the thread.

2. A shoe sewing machine having a straight hook needle and other stitch forming devices acting during sewing to draw loops of thread through the work and to tighten the loops against the work, and a thread cutter comprising a knife arranged to sever the thread in a loop withdrawn from the work by the needle, in combination with a forked guide member connected to the knife with its fork in parallel relation to and above the knife for engaging the needle within its fork to position the thread cutter relatively to the needle loop while the thread is being severed.

3. A shoe sewing machine having a straight hook needle and other stitch forming devices acting during sewing to draw loops of thread through the work and to tighten the loops against the work, and a thread cutter comprising a knife arranged to sever the thread in a loop withdrawn from the work by the needle, in combination with a guide member for positioning the thread cutter relatively to the needle loop arranged to surround the needle while the thread is being severed, and a'block having spaced parallel slots one above the other within which the thread cutter knife and the guide member are mounted.

4. A shoe sewing machine having a straight hook needle and other stitch forming devices acting during sewing to draw loops of thread through the work and to tighten the loops against the work, and a thread cutter comprising a knife arranged to sever the thread in a loop withdrawn from the work by the needle, in combination with a guide member connected in spaced relation to the knife for positioning the thread cutter relatively to the needle loop and arranged to surround and engage the needle while the thread is being severed, and a guard mounted with the knife to project between the cutting edge of the knife and the point on the work operated upon by the needle and in front of the cutting edge of the knife.

5. A shoe sewing machine having a straight hook needle and other stitch forming devices acting during sewing to draw loops of thread through the work and to tighten the loops against the work, a work support, a work clamping mem- No references cited. 

